MarketTrachea
Company Profile

Trachea

The trachea, also known as the windpipe, is a cartilaginous tube that connects the larynx to the bronchi of the lungs, allowing the passage of air, and so is present in almost all land vertebrate animals' lungs. The trachea extends from the larynx and branches into the two primary bronchi. At the top of the trachea, the cricoid cartilage attaches it to the larynx. The trachea is formed by a number of horseshoe-shaped rings, joined together vertically by overlying ligaments, and by the trachealis muscle at their ends. The epiglottis closes the opening to the larynx during swallowing.

Structure
An adult's trachea has an inner diameter of about and a length of about , wider in males than females. The trachea begins at the lower edge of the cricoid cartilage of the larynx at the level of sixth cervical vertebra (C6) Although trachea is a midline structure, it can be displaced normally to the right by the aortic arch. Nearby structures The trachea passes by many structures of the neck and chest (thorax) along its course. In front of the upper trachea lies connective tissue and skin. By the start of the fifth week, the left and right main bronchi have begun to form, initially as buds at the terminal end of the trachea. Mucus lines the ciliated cells of the trachea to trap inhaled foreign particles that the cilia then waft upward toward the larynx and then the pharynx where it can be either swallowed into the stomach or expelled as phlegm. This self-clearing mechanism is termed mucociliary clearance. Directly beneath this mucus layer lies the submucosa layer which is composed primarily of fibrous connective tissue and connects the mucosa to the rings of hyaline cartilage beneath. The trachea is surrounded by 16 to 20 rings of hyaline cartilage; these 'rings' are incomplete and C-shaped. Two or more of the cartilages often unite, partially or completely, and they are sometimes bifurcated at their extremities. The rings are generally highly elastic but they may calcify with age. File:Gray964.png|Cross-section File:2308 The Trachea-b.jpg|Cross-section of the trachea, with pseudostratified ciliated columnar epithelium and goblet cells labelled File:Cartilage01.JPG|Magnified cross-section of the cartilage of the trachea == Function ==
Function
The trachea's main function is to transport air to and from the lungs. It also helps to warm, humidify, and filter the air before it reaches the lungs. The trachea is made up of rings of cartilage, which help to keep it open and prevent it from collapsing. The inside of the trachea is lined with a mucous membrane, which produces mucus to help trap dirt and dust particles. The cilia, which are tiny hairs that line the mucous membrane, help to move the mucus and trapped particles up and out of the trachea. ==Clinical significance==
Clinical significance
Inflammation and infection Inflammation of the trachea is known as tracheitis, usually due to an infection. It is usually caused by viral infections, with bacterial infections occurring almost entirely in children. In patients who are in hospital, additional bacteria that may cause tracheitis include Escherichia coli, Klebsiella pneumoniae, and Pseudomonas aeruginosa. It can be due to congenital causes, or due to things that develop after birth, such as compression from nearby masses or swelling, or trauma. can lead to tracheal collapse, which often presents with a honking goose-like cough. Injury The trachea may be injured by trauma such as in a vehicle accident, or intentionally by another willfully inflicting damage for example as practiced in some martial arts. Intubation Tracheal intubation refers to the insertion of a tube down the trachea. This procedure is commonly performed during surgery, in order to ensure a person receives enough oxygen when sedated. The catheter is connected to a machine that monitors the airflow, oxygenation and several other metrics. This is often one of the responsibilities of an anaesthetist during surgery. In an emergency, or when tracheal intubation is deemed impossible, a tracheotomy is often performed to insert a tube for ventilation, usually when needed for particular types of surgery to be carried out so that the airway can be kept open. The provision of the opening via a tracheotomy is called a tracheostomy. Another method procedure can be carried, in an emergency situation, and this is a cricothyrotomy. Congenital disorders Tracheal agenesis is a rare birth defect in which the trachea fails to develop. The defect is usually fatal though sometimes surgical intervention has been successful. A tracheoesophageal fistula is a congenital defect in which the trachea and esophagus are abnormally connected (a ). This is because of abnormalities in the separation between the trachea and oesophagus during development. In adults, fistulas may occur because of erosion into the trachea from nearby malignant tumours, which erode into both the trachea and the oesophagus. Initially, these often result in coughing from swallowed contents of the oesophagus that are aspirated through the trachea, often progressing to fatal pneumonia; there is rarely a curative treatment. Sometimes as an anatomical variation one or more of the tracheal rings are formed as complete rings, rather than horseshoe shaped rings. These O rings are smaller than the normal C-shaped rings and can cause narrowing () of the trachea, resulting in breathing difficulties. An operation called a slide tracheoplasty can open up the rings and rejoin them as wider rings, shortening the length of the trachea. Slide tracheoplasty is said to be the best option in treating tracheal stenosis. Mounier-Kuhn syndrome is a rare congenital disorder of an abnormally enlarged trachea, characterised by absent elastic fibres, smooth muscle thinning, and a tendency to get recurrent respiratory tract infections. Replacement From 2008, operations have experimentally replaced tracheas, with those grown from stem cells, or with synthetic substitutes, however this is regarded as experimental and there is no standardised method. Difficulties with ensuring adequate blood supply to the replaced trachea is considered a major challenge to any replacement. Additionally, no evidence has been found to support the placement of stem cells taken from bone marrow on the trachea as a way of stimulating tissue regeneration, and such a method remains hypothetical. ==Other animals==
Other animals
Allowing for variations in the length of the neck, the trachea in other mammals is, in general, similar to that in humans. Generally, it is also similar to the reptilian trachea. Vertebrates In birds, the trachea runs from the pharynx to the syrinx, from which the primary bronchi diverge. Swans have an unusually elongated trachea, part of which is coiled beneath the sternum; this may act as a resonator to amplify sound. In some birds, the tracheal rings are complete, and may even be ossified. The distribution of spiracles can vary greatly among the many orders of insects, but in general each body segment can have only one pair of spiracles, each of which connects to an air cavity called atrium and has a relatively large tracheal tube behind it. The tracheae are invaginations of the cuticular exoskeleton that branch (anastomose) throughout the body with diameters from only a few micrometres up to 0.8 mm. Diffusion of oxygen and carbon dioxide takes place across the walls of the smallest tubes, called tracheoles, which penetrate tissues and even indent individual cells. Gas may be conducted through the respiratory system by means of active ventilation or passive diffusion. Unlike vertebrates, insects do not generally carry oxygen in their hemolymph. This is one of the factors that may limit their size. A tracheal tube may contain ridge-like circumferential rings of taenidia in various geometries such as loops or helices. Taenidia provide strength and flexibility to the trachea. In the head, thorax, or abdomen, tracheae may also be connected to air sacs. Many insects, such as grasshoppers and bees, which actively pump the air sacs in their abdomen, are able to control the flow of air through their body. In some aquatic insects, the tracheae exchange gas through the body wall directly, in the form of a gill, or function essentially as normal, via a plastron. Note that despite being internal, the tracheae of arthropods are lined with cuticular tissue and are shed during moulting (ecdysis). ==Additional images==
Additional images
File:Trachea (mammal) histology cross-section.png|alt=Trachea (mammal) cross-section high resolution|Trachea (mammal) cross-section high resolution File:Trachea (mammal) histology cross-section low mag.png|alt=Trachea (mammal) cross-section low resolution|Trachea (mammal) cross-section low resolution File:Larynx detailed.jpg|Trachea File:Gray954.png|Coronal section of larynx and upper part of trachea == References ==
tickerdossier.comtickerdossier.substack.com